Evidence has accumulated in recent years of increasing levels of fluorosis in fluoridated and unfluoridated communities. Also recently apparent is a dramatic decline in dental caries prevalence, not only in fluoridated communities, but in nonfluoridated communities, as well. Preliminary contributors to this decline in dental caries are community water fluoridation, widespread use of fluoridated dentifrices, use of dietary fluoride supplements and use of topical fluoride applications and rinses. However, since the levels of fluorosis substantially exceed levels predicted on the basis of data from Dean, prior to widespread intentional use of fluorides, we must consider the possibility that unintentional exposure to systemic fluorides may be contributory, e.g. accidental ingestion of fluoride toothpastes, inappropriate or excessive use of dietary fluoride supplements, use of high fluoride infant formulas and baby foods. The specific aims of this project are to: (1) document the distribution of mottled enamel (fluorosis) in fluoridated and unfluoridated communities, (2) identify possible determinants and correlates of fluorosis in the target populations, (3) compare findings from Aims Nos. 1 and 2 with analogous findings by Dean and McClure and their co-workers during the 1940's, and (4) evaluate the appropriateness of currently accepted norms regarding dietary fluoride supplementation and community water fluoridation. This study involves (1) clinical examinations of children ages 6, 7, 8, 12, 13 and 14 for DMFS and fluorosis, (2) questionnaire surveys regarding past fluoride exposure, (3) enamel biopsies and urinalyses to determine fluoride levels, (4) fluoride analyses of exfoliated deciduous teeth, and (5) fluoride analyses of common foodstuffs. If this study should confirm an increased level of fluorosis, establish relationships between fluorosis and prior exposure to unusual levels of fluoride and confirm evidence of increased fluoride in the food chain, it may be appropriate to reconsider the original assumptions that led to the current rationale for systemic fluoride therapy.